System for producing speed reduction signals for an elevator car



Dec. 10, 1968 3,415,344

SYSTEM FOR PRODUCING SPEED REDUCTION SiGNALS FOR AN ELEVATOR CAR Filed Dec. 20, 1965 fi. f A 6 32,

7'/ 0 1 75 1 0 H AKIRA ABE P/ zss's smzwz I INVENTORS I OA/ /%%Mv ATTORNEY United States Patent 3,415,344 SYSTEM FOR PRODUCING SPEED REDUCTION SIGNALS FOR AN ELEVATOR CAR Alrira Abe, 168 Tenno-cho, Takatsuki-shi, Osaka, Japan; Jukichi Takahashi, 53-7 Tojiin Minami-machi, Kita-ku, Kyoto, Japan; and Shosnke Morita, 37 Nagaoka-cho, Otokuni-gun, Kyoto, Japan Filed Dec. 20, 1965, Ser. No. 514,841 Claims priority, application Japan, Dec. 21, 1964, 39/72,434 6 Claims. (Cl. 187-29) This invention relates to a speed reduction system for an elevator car and more particularly to a system for producing signals to be applied to a drive means for an elevator car so as to gradually reduce its speed as it approaches a landing it has been called to serve.

In order to eliminate that uncomfortable feeling the passengers would experience upon abrupt stoppage of the car at a landing, it is necessary and customary to gradually reduce the speed of the car as it approaches the landing. In one prior art system, a model elevator car is provided in mechanically ganged relationship with the actual car so that the model car actuates a switch provided correspondingly to each of the landings to be served by the actual car so as to produce a signal for reducing its speed.

In such an arrangement, however, the model car must be provided, as well as mechanically movable switches to be actuated by the model car which have various disadvantages in comparison with static components.

There have been proposed various elevator car control systems in which electrical static components are employed in place of mechanical elements. To the best knowledge of the present inventors, however, in the prior art elevator car control systems there have been no disclosures whatsoever of any speed reduction system employing static components.

Accordingly, one object of the invention is to provide a system for producing speed reduction signals for an elevator car, which comprises static components.

Another object of the invention is to provide a system as aforesaid, in which no such model car as mentioned above need be provided.

Another object of the invention is to provide a system as aforesaid in which the speed of the elevator car is reduced a predetermined period of time after the car has passed the center of the distance between successive landings in a building, that is, between the landing it has been called to serve and the adjacent landing above or below.

Still another object of the invention is to provide a system as aforesaid which is capable of varying the time of initiating the speed reduction of the elevator car. This would be desirable in case there is a diiference in the distance between each adjacent pair of successive landings in a structure or building.

Other objects, features and advantages of the invention will become apparent from the following description of one preferred embodiment of the invention with reference to the accompanying drawings, wherein:

FIG. 1 is a circuit diagram of one embodiment of the invention; and

FIG. 2 shows difierent wave forms of the signals produced by some of the elements included in the circuit of FIG. 1.

Although the system of the invention is applicable to any desired number of landings or floors, the illustrated embodiment is designed to serve six floors designated by the numerals 1 through 6, respectively. At the center of the distance between each adjacent pair of successive floors, there are provided metallic pieces M1 through M5. The elevator car (not shown) is provided with a proximity 3,415,344 Patented Dec. 10, 1968 detector SA which is adapted to sen-seeach of the metallic pieces as it passes by it and produces an electrical signal. This signal is applied through a wave-form shaping circuit SC such as a Schmitt circuit to a circuit for producing signals corresponding to the position of the elevator car relative to the floors.

The circuit for producing position signals may be of any suitable construction, but in the illustrated embodiment it comprises a reversible counter RC. The counter RC is of such arrangement that with a signal being applied to the terminal AD, the counter is ready for summation, while with a signal being applied to the terminal SU, it is ready for subtraction. To put it in more detail, so long as the elevator car is located at the first floor, a signal appears at the output line L1 of the counter RC. When the car has started its up travel, a signal is applied to the terminal AD, and as the car passes by the metallic piece M1 placed between the first and second floors, the proximity detetor SA detects the metallic piece and produces a signal, which is applied in the form of a pulse to the reversible counter RC. Then, the signal on the line L1 disappears and at the same time a signal appears on the line L2 next thereto. In a similar manner, as the car passes by the other metallic pieces, a signal appears on the corresponding one of the lines L3 through L6, with the existing signal on the previous line having been disappeared. When the elevator car goes downward, a signal is applied to the terminal SU of the counter RC and the output line on which a signal appears will be shifted from L6 down to L1. Thus, as the elevator car moves up or down, a signal appears on the single one of the lines L1 through L6 which corresponds to the present position of the car relative to the floors. This position signal may be utilized to actuate a car-position indicator, or combined with a car-call signal to control the direction of running of the car.

The output pulse of the Schmitt circuit SC is applied to a timer TM1. The timer TM1 is so arranged and constructed as to produce an output signal a predetermined period of time after it received the output pulse from the Schmitt circuit. The timer comprises a series combina tion of a mono-stable multivibrator MVl, a differential circuit D1 and a rectifier R1. The operation of the timer is illustrated in FIG. 2, wherein the waves A, B and C represent the outputs of the Schmitt circuit, the multivibrator and the diflerentiator, respectively. When the output of the Schmitt circuit is applied to the mono-stable multivibrator, it is rendered astable for a predetermined period of time T1, during which a positive voltage is produced. The positive voltage is applied to the dilferential circuit D1, which produces a first positive differentiated pulse P1 and, after the period of time T1, a second negative differentiated pulse P2. Since the rectifier R1 is connected to the output side of the differentiator, the first pulse P1 cannot pass the rectifier but the second pulse P2 only passes therethrough to be applied to one of the input terminals of each of AND elements A1 and A2.

It will be seen that the arrangement of the illustrated embodiment is such that when the elevator car goes from the first up to the second floor and from the third down to the second floor and also from the second down to the first floor, the speed reduction signal is produced the same period of time T1 after the car has passed the center of the distance between the adjacent floors. However, when the elevator car goes from the second up to the third floor and also from the third up to the fourth floor and from the fifth down to the fourth floor and also from the fourth down to the third floor, the speed reduction signal is produced a period of time T2 which is difierent from T1 after the car has passed the center of the distance between the adjacent floors. To

this end, another timer TM2 is provided, which also comprises a series combination of a mono-stable multivibrator MV2, a differential circuit D2 and a rectifier R2. The multivibrator MV2 is so designed as to produce an output signal for a different period of time from in the case of the multivibrator MV1. When the elevator car goes from the fourth up to the fifth floor and also from the fifth up to the sixth floor, and from the sixth down to the fifth floor, the speed reduction signal is produced a different period of time T3 from both T1 and T2 after the car has passed midway between the adjacent floors. To this end, a third timer TM3 is provided, also comprising a series combination of a mono-stable multivibrator MV3, a differential circuit D3 and a rectifier R3. The multivihrator MV3 is so constructed as to produce an output for a different period of time from in the case of the previous two multivibrators MVl and MV2. Change of the period of time during which a mono-stable multivibrator becomes astable can be easily effected by changing the capacictance of a condenser connected to the control electrode of one of the pair of vacuum tubes or transistors constituting the multivibrator or the resistance of a resistor connected to the condenser.

The pulse signal passing through the rectifier R2 is applied to one of the input terminals of each of AND elements A3 and A4; while the signal passing through the rectifier R3 is applied to one of the input terminals of each of AND elements A5 and A6. The AND elements A1 through A6 are provided with second input terminals C1 through C6, respectively, to which is applied a car-call signal corresponding to the floor for which the elevator car service has been requested. When a car call for the first floor has been made, a signal applied to the terminal C1. In a similar manner, when a call for the second through sixth floors has been made, a signal is applied to the terminals C2 through C6, respectively. Needless to say, the signal disappears upon arrival of the car at the floor it has been called to serve. The AND elements A1 through A6 are provided third input terminals which are connected to the lines L1 through L6, respectively.

The AND elements A1 through A6 are also provided with output terminals S1 through S6, respectively, at which an output signal appears when an input signal is applied to all of the three input terminals at the same time. The signal appearing at the output terminals may be utilized to control a drive means (not shown) such as an electric motor for moving the car up or down to reduce its speed of rotation by, for example, changing the number of poles of the motor. A suitable control (not shown) may be provided to stop the motor when the car has arrived at the floor it has been called to serve.

In the illustrated embodiment, the three different timers TMl, TM2 and TM3 are for the purpose of effecting three different periods of time delay T1, T2 and T3, respectively. The number of timers may vary as occasions demand. In one case, a single timer may suffice having its output applied to one of the input terminals of each of the AND elements A1 through A6. In another case, two or more than four timers may be provided, with required circuit connections which will be apparent from the previous description.

In operation, suppose that the elevator car is located at the first floor. When the car has been called to serve the second floor, it moves upward. During the up travel, the proximity detector SA senses the metallic piece M1, whereupon one pulse is produced by the Schmitt circuit SC and applied to the reversible counter RC. This causes the existing signal on the line L1 to disappear and a signal to appear on the next line L2. The output of the Schmitt circuit is also applied as a trigger signal to the multivibrators MVl through MV3, so that after a different period of time a signal is produced by the rectifiers R1 through R3. These signals are applied to the AND elements Al through A6, However, since the car has been called at the second floor, a signal is applied to the terminal C2 of the AND element A2 only, with no signal being applied to the terminals C1, C3 through C6 of the other AND elements A1, A3 through A6. Consequently, these latter AND elements produce no output signal. With the signal on the line L2 being applied to the third input terminal of the AND element A2, it produces an output at the terminal S2 a predetermined period of time T1 after the proximity detector SA mounted on the car detected the metallic piece M1. The output signal at the terminal S2 is utilized to gradually reduce the speed of the car and the car approaches the second floor at the reduced speed to stop there.

Suppose that the elevator car is moving upward to serve the sixth floor. Although the proximity detector senses the metallic pieces M1 through M4, no signal is produced from the AND elements A1 through A5, but the AND element A6 produces an output signal a period of time T3 after the proximity detector SA sensed the metallic piece M5. As previously described, the period of time T3 is different from T1 or T2 in the case of the elevator car going, for example, from the first up to the second floor or from the third up to the fourth floor.

The above is true when the car has been called to serve any of the other floors above or any of the floors below.

Thus, in accordance with the invention, the timeelaying elements or timers which comprise electrical static elements are actuated by a signal upon passage of the elevator car through a point midway between the successive floors so as to produce a signal to reduce the speed of the car as it approaches the fioor it has been called to serve. And the signal that actuates the timer is produced when the proximity detector on the elevator car has detected the metallic piece provided at the center of the distance between the successive floors. This means that the system of the invention requires neither a model car such as employed in the prior art nor mechanical switches and the like operated by the model car. Since the metallic piece is positioned at the center of the distance between the adjacent floors, a single metallic piece between each adjacent pair of floors suffices for both the up and down travel of the elevator car. All these contribute to simplification of the system and its low manufacturing cost. Moreover, in accordance with the invention, the period of time delay provided by the timers can be easily set to a required value, and with a plurality of timers providing different periods of time delay, it is possible to vary the time of starting the speed reduction of the elevator car, depending upon the difference in the distance between the successive fioors the car is to serve.

Having illustrated and described preferred embodiments of the invention, it should be recognized that there are many other modifications and changes within the scope of the invention as defined in the appended claims.

What We claim is:

1. A system for producing a speed reduction signal for an elevator car serving a plurality of floors, comprising: a proximity detector provided on said elevator car; a member provided at the center of the distance between each adjacent pair of said floors and adapted to be detected by said proximity detector as said elevator car moves up or down; time-delaying means comprising electrical static components and adapted to be triggered by the output signal of said proximity detector to produce a first signal a predetermined period of time after said detector has detected said member; means for producing a second signal corresponding to that one of said floors which said elevator car has been called to serve; means for producing a third signal corresponding to the position of said elevator car relative to said floors; and means for producing a fourth signal upon reception of said first, second and third signals at the same time, said fourth signal being utilized to reduce the speed of said elevator car.

- 2. The system as defined in claim 1, wherein said timedelaying means comprise a single timer adapted to be triggered by the output of said proximity detector to produce a signal after a predetermined period of time delay.

3. The system as defined in claim 1, wherein said timedelaying means comprises a plurality of timers, each of which is adapted to be triggered by the output of said proximity detector to produce a signal after a predetermined period of time delay different from the time delays provided by the other timers.

4. The system as defined in claim 1, wherein said fourth signal producing means comprises AND elements, each of which is provided with a plurality of input terminals, to a different one of which are applied said first, second and third signals.

5. The system as defined in claim 2, wherein said timer comprises a series combination of a mono-stable vibrator being adapted to be triggered by the output of said proximity detector.

6. The system as defined in claim 3, wherein each of said plurality of timers comprises a series combination of mono-stable multivibrator, a differentiator and a rectifier, said multivibrator being adapted to be triggered by the output of said proximity detector.

References Cited UNITED STATES PATENTS 3,225,869 12/1965 Schibli 187-29 ORIS L. RADER, Primary Examiner.

multivibrator, a differentiator and a rectifier, said multi- 15 DUNCANSON, Assistant Examiner- 

1. A SYSTEM FOR PRODUCING A SPEED REDUCTION SIGNAL FOR AN ELEVATOR CAR SERVING A PLURALITY OF FLOORS, A COMPRISING: A PROXIMITY DETECTOR PROVIDED ON SAID ELEVATOR CAR; A MEMBER PROVIDED AT THE CENTER OF THE DISTANCE BETWEEN EACH ADJACENT PAIR OF SAID FLOORS AND ADAPTED TO BE DETECTED BY SAID PROXIMITY DETECTOR AS SAID ELEVATOR CAR MOVES UP OR DOWN; TIME-DELAYING MEANS COMPRISING ELECTRICAL STATIC COMPONENTS AND ADAPTED TO BE TRIGGERED BY THE OUTPUT SIGNAL OF SAID PROXIMITY DETECTOR TO PRODUCE A FIRST SIGNAL A PREDETERMINED PERIOD OF TIME AFTER SAID DETECTOR HAS DETECTED SAID MEMBER; MEANS FOR PRODUCING A SECOND SIGNAL CORRESPONDING TO THAT ONE OF SAID FLOORS WHICH SAID ELEVATOR CAR HAS BEEN CALLED TO SERVE; MEANS FOR PRODUCING A THIRD SIGNAL CORRESPONDING TO THE POSITION OF SAID ELEVATOR CAR RELATIVE TO SAID FLOORS; AND MEANS FOR PRODUCING A FOURTH SIGNAL UPON RECEPTION OF SAID FIRST, SECOND AND THIRD SIGNALS AT THE SAME TIME, AND FOURTH SIGNAL BEING UTILIZED TO REDUCE THE SPEED OF SAID ELEVATOR CAR. 